title: Hypogammaglobulinemia in pediatric systemic lupus erythematosus.
abstract: OBJECTIVE
  Systemic lupus erythematosus (SLE) is a systemic autoimmune disease typically associated with elevated serum immunoglobulin G (IgG). Hypogammaglobulinemia in SLE patients has been attributed to immunosuppressive treatment or a transient effect associated with nephrotic syndrome. We retrospectively reviewed pediatric SLE patients from a single institution to identify patients with hypogammaglobulinemia and risk factors for hypogammaglobulinemia.
  
  
  METHODS
  A total of 116 pediatric SLE cases from 1997 to 2011 were reviewed and patients with hypogammaglobulinemia (IgG < 500 mg/dl) were identified. The two cohorts were evaluated for association with age, sex, presence of lupus nephritis at SLE diagnosis, disease activity at diagnosis, initial IgG level, and drug treatment.
  
  
  RESULTS
  Eighty-six patients were included in our study, with a median age of 15 years and a median follow-up of 39.5 months. Seven percent (six of 86) of patients had hypogammaglobulinemia with a median onset of 27 months (0-72 months) after SLE diagnosis. Significant associations were noted for white race (p value 0.029), male sex (p value 0.009), and the presence of lupus nephritis at SLE diagnosis (p value 0.004). Use of immunosuppressive treatment did not show a statistical association with hypogammaglobulinemia, although two of the patients with hypogammaglobulinemia did receive rituximab. Most patients with hypogammaglobulinemia received intravenous immunoglobulin (IVIG) replacement therapy because of infections and/or concern for infection.
  
  
  CONCLUSIONS
  Measurement of immunoglobulin levels during treatment in SLE could help identify patients with hypogammaglobulinemia who might require more aggressive follow-up to monitor for increased risk of infection and need for IVIG treatment. A prospective study is needed to validate associated risk factors identified in this study.
authors.affiliation: 1Department of Pediatrics, Division of Rheumatology, Washington University School of Medicine, MO, USA; and.
authors.forename: E
authors.initials: E
authors.lastname: Lim
authors.forename: Y
authors.initials: Y
authors.lastname: Tao
authors.forename: A J
authors.initials: AJ
authors.lastname: White
authors.forename: A R
authors.initials: AR
authors.lastname: French
authors.forename: M A
authors.initials: MA
authors.lastname: Cooper
mesh_terms: D000293:Adolescent; D000361:Agammaglobulinemia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000208:ethnology / Q000276:immunology*; D000367:Age Factors; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000208:ethnology / Q000276:immunology*; D008181:Lupus Nephritis / Q000097:blood / Q000276:immunology; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D044465:White People
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; D007166:Immunosuppressive Agents
keywords: Systemic lupus erythematosus; hypogammaglobulinemia; pediatrics